CN117529396A - Mold for forming tire and tire production method - Google Patents
Mold for forming tire and tire production method Download PDFInfo
- Publication number
- CN117529396A CN117529396A CN202180099314.XA CN202180099314A CN117529396A CN 117529396 A CN117529396 A CN 117529396A CN 202180099314 A CN202180099314 A CN 202180099314A CN 117529396 A CN117529396 A CN 117529396A
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- tire
- tread
- mold
- forming
- design face
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- 238000000465 moulding Methods 0.000 claims abstract description 26
- 238000004073 vulcanization Methods 0.000 claims abstract description 19
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000002093 peripheral effect Effects 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 229920003051 synthetic elastomer Polymers 0.000 description 2
- 239000005061 synthetic rubber Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 102200082816 rs34868397 Human genes 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/02—Moulds or cores; Details thereof or accessories therefor with incorporated heating or cooling means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/20—Opening, closing or clamping
- B29C33/26—Opening, closing or clamping by pivotal movement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2030/00—Pneumatic or solid tyres or parts thereof
Abstract
The present invention provides a tire molding die (1) and a tire production method using the same, the tire molding die (1) is equipped with an annular tread molding portion (20), the tread molding portion (20) is configured to open and close when a plurality of segments (21) are moved in a radial direction, and has a plurality of design face dividing die portions (23, 24), each of the plurality of design face dividing die portions (23, 24) is equipped with a tread design face (20 c) for molding a tread (2 c) of a tire (2), is arranged side by side in a circumferential direction of the segments (21), and is configured to rotate about a rotatable shaft (26) parallel to an axis of the tread molding portion (20) when the tread molding portion (20) is opened after the tire (2) has undergone vulcanization molding.
Description
Technical Field
The present disclosure relates to a mold for forming a tire and a tire production method.
Background
In a known conventional mold for forming a tire used in vulcanization molding of an unvulcanized green tire to produce the tire, it is known that an annular tread molding portion (tread mold) for forming a tread of the tire is divided into a plurality of segments arranged in a circumferential direction and is configured to be opened and closed by moving each of the segments in a radial direction (for example, see patent documents 1 to 3).
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2000-326332
Patent document 2: japanese patent laid-open No. 2000-334740
Patent document 3: japanese patent laid-open No. 2009-149979
Disclosure of Invention
Problems to be solved by the invention
In the above-described conventional mold for forming a tire, the tread design surface oriented toward the radially inner side of each segment is generally provided with protrusions such as ribs or vanes protruding from the tread design surface toward the radially inner side so as to form a tread pattern having irregularities constituted by grooves and sipes on the tread of the formed tire, for example.
However, in a configuration in which the tread design surface is provided with the projections, when the tire is demolded from the tread forming portion by moving the segments toward the radially outer side after vulcanization forming, high undercut resistance of the tread is caused by the projections, particularly, the projections on both circumferential end sides of the segments. Thus, in the case of forming a tire having a complicated tread pattern, for example, the above-described excessively high undercut resistance may cause defects such as permanent deformation and protrusion breakage in the tread of the tire after demolding.
The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to provide a mold for forming a tire and a tire production method, which can reduce undercut resistance of a tread caused by a protrusion at the time of tire demolding.
Solution for solving the problem
The mold for forming a tire of the present disclosure is a mold for forming a tire for vulcanization molding an unvulcanized green tire into a tire, the mold comprising: an annular tread forming portion divided into a plurality of segments arranged in a circumferential direction and configured to be opened and closed by moving each of the segments in a radial direction, wherein each of the segments includes: a plurality of design face dividing mold portions each including a tread design face for forming a tread of the tire, the plurality of design face dividing mold portions being arranged in a circumferential direction of the segment, and configured to rotate about a rotatable shaft parallel to an axis of the tread forming portion when the tread forming portion is opened after vulcanization forming of the tire.
In an embodiment, the mold for forming a tire of the present disclosure may be constructed in the following manner: each of the segments includes a retainer that is driven radially outward by a container when the tread forming portion is opened, and each of the plurality of design face-dividing mold portions is rotatably supported by the rotatable shaft with respect to the retainer.
In an embodiment, a mold for forming a tire of the present disclosure may be configured to: the mold includes two pieces of the design face dividing mold portions, wherein a rotatable shaft corresponding to one of the design face dividing mold portions is arranged at one circumferential end side of the holder, and a rotatable shaft corresponding to the other of the design face dividing mold portions is arranged at the other circumferential end side of the holder.
In an embodiment, the mold for forming a tire of the present disclosure may be constructed in the following manner: the design surface dividing mold portion includes a back plate portion and a pair of side plate portions extending radially inward from both ends of the back plate portion in the axial direction and supported by the rotatable shaft at the back plate portion.
In an embodiment, a mold for forming a tire of the present disclosure may be configured to: a spring member is attached between the design face dividing mold portion corresponding to the spring member and the holder to hold the design face dividing mold portion corresponding to the spring member at a predetermined position, and when the tread forming portion is opened, the spring member is elastically deformed to allow the design face dividing mold portion to rotate relative to the holder.
The tire production method of the present disclosure is a tire production method of vulcanizing and molding an unvulcanized green tire by using a mold for forming a tire, the mold including an annular tread molding portion divided into a plurality of segments arranged in a circumferential direction and configured to be opened and closed by radially moving each of the segments, wherein when the tread molding portion is opened by radially moving each of the segments to an outside, the tire is demolded from the tread molding portion while each of a plurality of design face dividing mold portions provided in the segments in a circumferential arrangement is rotated about a rotatable shaft parallel to an axis of the tread molding portion.
ADVANTAGEOUS EFFECTS OF INVENTION
The present disclosure may provide a mold for forming a tire and a tire production method, which may reduce undercut resistance of a tread caused by a protrusion when the tire is demolded.
Drawings
In the drawings:
FIG. 1 is a cross-sectional view of a mold for forming a tire according to an embodiment of the present disclosure illustrated in a front view;
FIG. 2 is a cross-sectional view of the tread forming portion illustrated in FIG. 1 illustrated in a plan view;
FIG. 3 is a cross-sectional view of the mold for forming a tire illustrated in FIG. 1 when the mold for forming a tire is opened, illustrated in a front view;
FIG. 4 is a cross-sectional view of the tread forming portion illustrated in FIG. 1, illustrated in a plan view, when the tread forming portion is opened;
fig. 5 is an enlarged cross-sectional view of a detailed structure of a main portion of the mold for forming a tire illustrated in fig. 1 illustrated in a front view;
FIG. 6 is a sectional view of one segment illustrated in FIG. 5 in plan view;
FIG. 7 is a cross-sectional view illustrating a detail of the spring member illustrated in FIG. 6; and
fig. 8 is a sectional view of one segment illustrated in fig. 5 at the time of demolding of the tire illustrated in a plan view.
Detailed Description
By way of example, a mold for forming a tire and a tire production method according to embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In this respect, common components and parts appearing in the drawings have the same reference numerals.
The mold 1 for forming a tire illustrated in fig. 1 according to the embodiment of the present disclosure is used to form an unvulcanized (before vulcanization) green tire based on synthetic rubber into a predetermined shape in the case where the green tire is vulcanized to produce a tire 2.
In this regard, the tire 2 is a hollow tire based on an elastomer, which includes a pair of sidewalls 2a, 2b and a tread 2c, and is formed so as to provide a space for filling a gas such as air or nitrogen inside the tire 2.
The mold 1 for forming a tire includes a sidewall forming portion 10 and a tread forming portion 20.
For example, the sidewall forming section 10 may include an annular lower sidewall forming section 11 fixed to the top surface of the lower container 3 and an annular upper sidewall forming section 12 fixed to the bottom surface of the upper container 4.
The sidewall formation 10 may arrange (house) the annular tire 2 or green tire between the lower sidewall formation 11 and the upper sidewall formation 12 in the following orientation: this orientation makes the central axis of the green tire coaxial with the central axis O of the sidewall forming section 10. The lower sidewall forming section 11 includes a lower sidewall design surface 11a, the lower sidewall design surface 11a being in an annular form about the central axis O and oriented in an upward direction. The lower sidewall forming section 11 may form the outer surface of the sidewall 2a of one side (both oriented in the downward direction in fig. 1) of the tire 2 or the green tire by the lower sidewall design surface 11 a. Likewise, the upper sidewall forming section 12 includes an upper sidewall design surface 12a, the upper sidewall design surface 12a being annular in form about the central axis O and oriented in a downward direction. The upper sidewall forming section 12 may form the outer surface of the sidewall 2b of the tire 2 or the other side of the green tire (both oriented in the upward direction in fig. 1) by an upper sidewall design surface 12 a. As shown in fig. 3, by moving the upper container 4 upward (the direction in which the upper container 4 and the lower container 3 move away from each other along the central axis of the tire 2) with respect to the lower container 3, the sidewall forming section 10 is opened, and the tire 2 is demolded from the sidewall forming section 10. By moving the upper container 4 downwardly to the initial position of the upper container 4 as shown in fig. 1, the sidewall formation 10 in the open configuration is closed to allow the tire 2 or green tire to be formed.
In this regard, the configuration of the sidewall forming part 10 may be appropriately modified, and examples of such modification include a configuration in which the sidewall forming part 10 is opened by moving the lower container 3 downward with respect to the upper container 4.
The tread forming portion 20 is annular and coaxial with the sidewall forming portion 10, and is disposed adjacent to the radially outer sides of the lower sidewall forming portion 11 and the upper sidewall forming portion 12. An inner circumferential surface of the tread forming portion 20 oriented radially inward is a tread design surface 20a for forming an outer circumferential surface of the tread 2c of the tire 2.
As shown in fig. 2, the tread forming portion 20 is divided into a plurality of segments 21 arranged in the circumferential direction. Each of the segments 21 is circular arc-shaped in plan view, and the segments 21 are combined in a circumferential arrangement to constitute a tread forming portion 20, the tread forming portion 20 being an annular mold as a whole. In this embodiment, the tread forming portion 20 is divided into 9 segments 21 having the same length in the circumferential direction. In this regard, the number of divisions of the tread forming portion 20 in the circumferential direction is preferably, but not limited to, 7 to 13, and may be appropriately changed.
As shown in fig. 1, the outer peripheral surface of each segment 21 oriented radially outward is fixed to the inside of the intermediate container 5 corresponding to each segment 21, and each segment 21 is driven by the intermediate container 5 to move radially about the axis of the tread forming portion 20 (central axis O). By moving each segment 21 in the radial direction, the tread forming portion 20 can be opened and closed.
More specifically, the outer peripheral surface of the intermediate container 5 oriented radially outward is provided with a tapered surface 5a, and the tapered surface 5a is inclined such that the outer diameter of the tapered surface 5a gradually becomes smaller toward the upward direction. An annular outer ring 6 disposed radially outside the intermediate tank 5 is fixed to the bottom surface of the upper tank 4. The inner peripheral surface of the outer ring 6 oriented radially inward is provided with a tapered surface 6a, the tapered surface 6a being inclined such that the outer diameter of the tapered surface 6a gradually becomes smaller toward the upward direction. For example, the outer ring 6 is coupled with each intermediate container 5 by using a guide member (not shown) in such a manner that the tapered surface 6a slides in the up-down direction along the tapered surface 5a of the intermediate container 5.
When the upper container 4 moves upward relative to the lower container 3, the outer ring 6 moves upward relative to each intermediate container 5 while the tapered surface 6a slides along the tapered surface 5a of the intermediate container 5. Therefore, as shown in fig. 3, each intermediate container 5 moves radially outward centering on the axis of the tread forming portion 20. When each intermediate container 5 moves radially outward about the axis of the tread forming portion 20, as shown in fig. 3 and 4, each segment 21 is driven by the intermediate container 5 corresponding to each segment 21 to move radially outward together with the intermediate container 5. Accordingly, the tread forming portion 20 is opened to be in a position where the tread design surface 20a is separated from the tread 2c of the tire 2 or the green tire. In this regard, the tread forming portion 20 may be configured such that, after the tread forming portion 20 is opened as described above, the tread forming portion 20 suspended by the outer ring 6 moves upward together with the upper case 4 to a position (upper position with respect to the position shown in fig. 3) where the formed tire 2 can be removed. When the upper container 4 moves downward to the initial position shown in fig. 1, the tread forming portion 20 moves downward to a position adjacent to the lower sidewall forming portion 11. Subsequently, the outer ring 6 moves downward with respect to each intermediate container 5, and each intermediate container 5 moves toward the radially inner side centering on the axis of the tread forming portion 20. Thus, as shown in fig. 1 and 2, each segment 21 is driven by the intermediate container 5 corresponding to each segment 21 to move toward the radially inner side together with the intermediate container 5, and the tread forming portion 20 is closed to allow formation of the tire 2 or the green tire.
As described above, in the mold 1 for forming a tire of the present embodiment, the annular tread forming portion 20 is divided into the plurality of segments 21 arrayed in the circumferential direction, and is configured to be opened and closed by moving each segment 21 in the radial direction.
The opening and closing mechanism of the tread forming portion 20 is not limited to the configuration using the outer ring 6, but may take a variety of configurations.
The mold 1 for forming a tire includes a bladder 7, the bladder 7 being disposed inside a green tire and being inflated by supplying pressurized steam. Also, the mold 1 for forming a tire includes a heater (not shown) for heating the sidewall forming portion 10 and the tread forming portion 20. The position of the heater can be appropriately determined.
As shown in fig. 5 and 6, in the mold 1 for forming a tire of the present embodiment, each of the plurality of segments 21 constituting the tread forming portion 20 includes a plurality of design face dividing mold portions 23, 24, and each of the plurality of design face dividing mold portions 23, 24 is arranged in the circumferential direction of the segment 21. In the present embodiment, each of the plurality of segments 21 includes two design face dividing mold portions 23, 24.
In the present embodiment, each segment 21 includes a retainer 22. A plurality of design surface dividing mold portions 23, 24 are arranged radially inward of the holder 22.
The holder 22 is a portion that is fixed to the intermediate container 5 and is driven toward the radially outer side by the intermediate container 5 when the tread forming portion 20 is opened. When the tread forming portion 20 is closed, the retainer 22 is driven by the intermediate container 5 toward the radially inner side. The holder 22 may be formed by cutting a block made of metal such as low carbon steel, for example.
In the present embodiment, the holder 22 is detachably fixed to the intermediate container 5. Accordingly, it is possible to selectively attach the plural types of segments 21 of the tread design surface 20a having mutually different shapes to the intermediate container 5, and thereby the mold 1 for forming a tire is suitable for producing plural types of tires 2 having mutually different tread patterns.
The two design surface dividing mold portions 23, 24 are portions constituting a tread design surface 20a for forming the tread 2c of the tire 2. Each of the two design surface dividing mold portions 23, 24 is arc-shaped in plan view, and a surface oriented toward the radially inner side of the design surface dividing mold portions 23, 24 constitutes a circumferential dividing portion of the tread design surface 20 a. The two design face dividing mold portions 23, 24 contact each other at the circumferential end faces of the two design face dividing mold portions 23, 24. In other words, the tread design surface 20a of the tread forming portion 20 is divided in the circumferential direction and is provided on the design surface dividing mold portions 23, 24 provided on each of the plurality of segments 21. Therefore, the tread forming portion 20 is divided into 9 pieces in the circumferential direction, and the tread design surface 20a is divided into 18 pieces in the circumferential direction.
As shown in fig. 5, each tread design surface 20a provided on the design surface dividing mold portions 23, 24 is provided with a plurality of protrusions 25, the plurality of protrusions 25 protruding radially inward from the tread design surface 20 a. The plurality of projections 25 are used to form grooves or sipes, for example, constituting a tread pattern, on the tread 2c of the tire 2 at the time of vulcanization molding. The plurality of protrusions 25 may have various shapes or sizes (lengths) customized to the tread pattern, such as a plurality of protrusions 25 extending in the tire width direction and a plurality of protrusions 25 extending in the tire circumferential direction.
The design face separation mold portions 23, 24 are preferably formed by casting a metal material having high thermal conductivity such as an aluminum alloy. In this case, for example, the rib-like or blade-like projections 25 made of steel may be provided by being integrated with the design surface dividing mold portions 23, 24 in the casting of the design surface dividing mold portions 23, 24.
Each of the design surface dividing mold portions 23, 24 is rotatably supported with respect to the holder 22 by a rotatable shaft 26 parallel to the axis (central axis O) of the tread forming portion 20. When the tread forming portion 20 is opened after vulcanization forming of the tire 2, each of the design face dividing mold portions 23, 24 is rotated around the rotatable shaft 26 with respect to the holder 22.
More specifically, each of the design face dividing mold portions 23, 24 is supported rotatably with respect to the holder 22 by two rotatable shafts 26 parallel to the axis of the tread forming portion 20, that is, two rotatable shafts 26 arranged coaxially with each other in the width direction of the tire 2. Each of the design face split mold portions 23, 24 is configured to rotate about the rotatable shaft 26 with respect to the holder 22 from a predetermined position toward the radially inner side. In this regard, the term "predetermined position" refers to a position as follows: at this position, each of the design face dividing mold portions 23, 24 is in a posture in which the tread design faces 20a provided on the design face dividing mold portions 23, 24 are continuously connected to each other in a circumferentially aligned manner. In the case shown, the rotatable shaft 26 is divided into two pieces, one for supporting the upper part of the design face dividing mold portions 23, 24 on the segment 21 and the other for supporting the lower part of the design face dividing mold portions 23, 24 on the segment 21. However, instead of such a rotatable shaft 26, it is also possible to use a rotatable shaft 26 which extends through the design face dividing die sections 23, 24.
The design face dividing mold portion 23 disposed at the circumferential one end side of the segment 21 is preferably configured to be supported by the rotatable shaft 26 on the holder 22 at a position located at the circumferential one end side of the segment 21 on one side with respect to the circumferential center of the design face dividing mold portion 23. Likewise, the design face dividing mold portion 24 disposed on the other end side in the circumferential direction of the segment 21 is preferably configured to be supported by the rotatable shaft 26 on the holder 22 at a position located on the other end side in the circumferential direction of the segment 21 on one side with respect to the circumferential center of the design face dividing mold portion 24.
In the present embodiment, the rotatable shaft 26 corresponding to the design face dividing mold portion 23 arranged at the circumferential one end side of the segment 21 is arranged at the circumferential one end side of the holder 22. A rotatable shaft 26 corresponding to the design face dividing mold portion 24 arranged at the other end side in the circumferential direction of the segment 21 is arranged at the other end side in the circumferential direction of the holder 22. In other words, on the one hand, the design face split mold portion 23 is supported by the rotatable shaft 26 rotatably with respect to the holder 22 at a position closer to the one end side in the circumferential direction of the holder 22 than the circumferential center of the design face split mold portion 23. On the other hand, the design surface dividing mold portion 24 is rotatably supported by the rotatable shaft 26 at a position closer to the other end side in the circumferential direction of the holder 22 than the circumferential center of the design surface dividing mold portion 24.
In the present embodiment, the two design surface dividing mold portions 23 and 24 are formed to include the respective back plate portions 23a and 24a and the respective paired side plate portions 23b and 24b, and the side plate portions 23b and 24b extend radially inward from both ends in the axial direction (central axis O) of the respective back plate portions 23a and 24 a. The two design face dividing mold portions 23, 24 are supported by rotatable shafts 26 at the respective back plate portions 23a, 24 b.
As shown in fig. 6, the pin member 27 is fixed to the design face split mold portions 23, 24 at a predetermined distance from the rotatable shaft 26 in the radial direction of the rotatable shaft 26, and movement of the pin member 27 is restricted by a slit 28 provided on the holder 22. Therefore, the rotation range of the design face dividing mold portions 23, 24 about the rotatable shaft 26 is limited to a predetermined range. In this regard, the pin member 27 and the slit 28 may not be provided.
The tread forming portion 20 may be configured to include a spring member 29, the spring member 29 being attached between the design face dividing mold portions 23, 24 corresponding to the spring member 29 and the holder 22 to hold the design face dividing mold portions 23, 24 corresponding to the spring member 29 at a predetermined position, and being elastically deformed to allow the design face dividing mold portions 23, 24 to rotate relative to the holder 22 when the tread forming portion 20 is opened. As shown in fig. 7, in the present embodiment, the bolts 30 are fixed to the back surfaces of the design surface dividing mold portions 23, 24, and the spring members 29 are arranged between the heads 30a of the bolts 30 arranged in the holes 22a provided in the holder 22 and the bottom wall of the holes 22a of the holder 22. The spring member 29 is a helical compression spring. The spring member 29 biases a portion of the design surface dividing mold portions 23, 24 at a distance from the rotatable shaft 26 toward a direction in which the portion is guided to the holder 22. Accordingly, the spring member 29 holds the design face dividing mold portions 23, 24 at a predetermined position, and when the tread forming portion 20 is opened, the spring member 29 elastically deforms (compressively deforms) between the head 30a of the bolt 30 and the bottom wall of the hole 22a to allow the design face dividing mold portions 23, 24 to rotate relative to the holder 22.
Next, a method of producing the tire 2 having a predetermined shape by vulcanization molding the green tire using the mold 1 for forming a tire having the above-described structure, that is, a tire production method as an embodiment of the present disclosure will be described.
First, the sidewall forming part 10 and the tread forming part 20 are opened to arrange the green tire inside the mold 1 for forming a tire, and then, the sidewall forming part 10 and the tread forming part 20 are closed.
Next, the bladder 7 is inflated by supplying pressurized steam to the bladder 7 disposed inside the green tire. Accordingly, the sidewalls of the green tire are respectively pressed against the lower sidewall design surface 11a and the upper sidewall design surface 12a of the sidewall forming portion 10, and the tread is pressed against the tread design surface 20a of the tread forming portion 20. In this case, the sidewall forming portion 10 and the tread forming portion 20 are heated using a heater, and this heat causes vulcanization of the synthetic rubber constituting the green tire to form the tire 2 having a predetermined shape.
After the formation of the tire 2 is completed, the sidewall forming portion 10 and the tread forming portion 20 are opened to remove the formed tire 2.
After vulcanization molding of the tire 2, when each segment 21 is moved to the radially outer side to open the tread molding portion 20, a driving force required for resisting the tread 2c of the tire 2 coming into close contact with the inner peripheral surface of the tread design surface 20a and for resisting the undercut resistance generated between the tread 2c of the tire 2 and the projection 25 is applied to each of the design surface dividing mold portions 23, 24 with the retainer 22 as a medium. At this time, each of the two design face dividing mold portions 23, 24 in each segment 21 is arranged at one side or the other side in the circumferential direction of the segment 21 or the retainer 22 in such a manner as to be offset from the circumferential center of the segment 21 or the retainer 22. Therefore, a driving force is applied to each of the design face dividing mold portions 23, 24 at a position circumferentially offset from the circumferential center of the holder 22. Therefore, when the tread forming portion 20 is opened after vulcanization forming of the tire 2, as shown in fig. 8, each of the design surface dividing mold portions 23, 24 spontaneously rotates (shake action) around the rotatable shaft 26 in such a manner that the end portion of the side adjacent to the circumferential center of the holder 22 is moved away from the holder 22 toward the radially inner side.
As described above, in the tire production method by using the mold 1 for forming a tire of the present embodiment, when the tread forming portion 20 is opened after vulcanization molding of the tire 2, the tire 2 can be demolded from the tread forming portion 20 with each of the design face dividing mold portions 23, 24 rotating about the rotatable shaft 26 parallel to the axis of the tread forming portion 20. Therefore, when the tire 2 is released from the tread forming portion 20, each of the design surface dividing mold portions 23, 24 rotates to allow the protrusion 25 to be in a posture in which the undercut resistance of the tread 2c of the tire 2 caused by the protrusion 25 is reduced. Therefore, the undercut resistance of the tread 2c caused by the protrusion 25 at the time of demolding of the tire 2 can be reduced.
In particular, in the present embodiment, the rotatable shaft 26 corresponding to the design face dividing mold portion 23 arranged at the circumferential one end side of the segment 21 is arranged at the circumferential one end side of the holder 22. A rotatable shaft 26 corresponding to the design face dividing mold portion 24 arranged at the other end side in the circumferential direction of the segment 21 is arranged at the other end side in the circumferential direction of the holder 22. Therefore, when the tread forming portion 20 is opened, each of the design face dividing mold portions 23, 24 can be rotated with respect to the holder 22 more reliably. Further, each of the design face dividing mold portions 23, 24 may be rotated as follows: so that the protrusions 25 are in a posture in which the undercut resistance of the tread 2c of the tire 2 caused by the protrusions 25 is reduced at both end sides in the circumferential direction of the holder 22 which generates particularly high undercut resistance. Therefore, the undercut resistance of the tread 2c caused by the protrusion 25 at the time of demolding of the tire 2 can be reduced more effectively.
Therefore, the mold 1 for forming a tire or the tire production method of the present embodiment can suppress defects such as permanent deformation in the formed tread 2c of the tire 2 and breakage of the protrusions 25 caused by excessively high undercut resistance when the tire 2 is released from the tread forming portion 20.
Further, by rotating each of the design face dividing mold portions 23, 24, the tread 2c of the tire 2 is gradually released from the circumferential one end side of each of the design face dividing mold portions 23, 24. Accordingly, the outside air is gradually introduced between the tread design surface 20a and the tread 2c from the circumferential both end sides of the tread design surface 20a and the tread 2c to allow the tread 2c of the tire 2 in close contact with the tread design surface 20a to be peeled off from the tread design surface 20a more effectively. Therefore, the tire 2 can be more easily released from the tread forming portion 20.
Further, the mold 1 for forming a tire or the tire production method of the present embodiment can reduce the undercut resistance of the tread 2c caused by the protrusion 25 when the tire 2 is demolded, and also allow the tread 2c of the tire 2 in close contact with the tread design surface 20a to be peeled off from the tread design surface 20a more effectively. Accordingly, the driving force applied to the segment 21 at the time of demolding of the tire 2 can be reduced, and therefore, the entire production apparatus including the mold 1 for forming the tire can be miniaturized to reduce the production cost.
Further, the mold 1 for forming a tire or the tire production method of the present embodiment can reduce the undercut resistance of the tread 2c caused by the protrusion 25 when the tire 2 is demolded. Accordingly, the tire 2 having a more complex tread pattern can be produced relatively easily. Thus, the production flexibility of the tire 2 having a complex tread pattern can be improved.
In the mold 1 for forming a tire of the present embodiment, the rotatable shaft 26 corresponding to the design face dividing mold portion 23 arranged at the circumferential one end side of the segment 21 is arranged at the circumferential one end side of the holder 22. A rotatable shaft 26 corresponding to the design face dividing mold portion 24 arranged at the other end side in the circumferential direction of the segment 21 is arranged at the other end side in the circumferential direction of the holder 22. The two design face dividing mold portions 23, 24 include respective back plate portions 23a, 24a and respective paired side plate portions 23b, 24b extending radially inward from both axial ends of the respective back plate portions 23a, 24a, and are supported by rotatable shafts 26 at the respective back plate portions 23a, 24 b. Therefore, when the two design face separation mold portions 23, 24 are at predetermined positions, the circumferential end faces of the two design face separation mold portions 23, 24 contact each other to suppress the generation of burrs in the tread 2c of the vulcanization molded tire 2. Further, when the segment 21 is moved radially outward to release the tire 2 from the tread forming portion 20, each of the design face dividing mold portions 23, 24 may spontaneously rotate with respect to the holder 22.
Moreover, in the mold 1 for forming a tire of the present embodiment, the tread forming portion 20 includes the spring member 29, the spring member 29 is attached between the design face dividing mold portions 23, 24 corresponding to the spring member 29 and the holder 22 to hold the design face dividing mold portions 23, 24 corresponding to the spring member 29 at a predetermined position, and when the tread forming portion 20 is opened, the spring member 29 is elastically deformed to allow the design face dividing mold portions 23, 24 to rotate relative to the holder 22. Therefore, each of the design surface dividing mold portions 23, 24 is ensured to be held at a predetermined position at the time of vulcanization molding of the green tire to improve the formability of the tire 2. Further, when the tread forming portion 20 is opened after vulcanization forming of the tire 2, each of the design face dividing mold portions 23, 24 can spontaneously rotate about the rotatable shaft 26 with respect to the holder 22. Therefore, the undercut resistance of the tread 2c caused by the protrusion 25 at the time of demolding of the tire 2 can be reduced.
Example
As an example of the mold for forming a tire, a mold for forming a tire having the above-described configuration is employed, in which:
the design face dividing die part is made of an aluminum alloy (AC 4C) and the difference between the maximum inner diameter and the minimum inner diameter is 35mm;
the protrusions were made of stainless steel plate (SUS 304H material) and had a thickness of 0.3mm;
the holder is made of low carbon steel (S45C equivalent material) by machining;
the spring member deforms about 10mm under an applied load of 100 kg;
when the segments are moved 16mm radially outward, each of the design face split mold sections is rotated 5 degrees. The mold for forming the tire was used to form a tire having an inner diameter of 600mm and a tire width of 255mm, and an external force (driving force to be applied to the holder) required for demolding the tire was measured. Therefore, when compared with the mold for forming a tire of the comparative example having a configuration in which the design face dividing mold portion is not rotated, it has been demonstrated that the mold for forming a tire of the example can reduce the external force by substantially 30%.
Of course, the present disclosure is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the present disclosure.
For example, in the above embodiment, each of the plurality of segments 21 includes two design face dividing mold portions 23, 24; however, each of the plurality of segments 21 may include three or more design face segmentation mold sections.
Furthermore, in the above-described embodiment, each segment 21 is provided with the holder 22, and the two design surface dividing mold portions 23, 24 are supported by the rotatable shaft 26 so as to be rotatable with respect to the holder 22. However, it is also possible to dispense with the holder 22 and to support the two design face separation mold portions 23, 24 on another member such as the intermediate container 5 via the rotatable shaft 26.
Furthermore, in the above embodiment, the holder 22 of the segment 21 is fixed to the intermediate container 5. However, the holder 22 may be integrated with the intermediate container 5.
List of reference numerals
1 mould for forming tyres
2 tyre
2a sidewall
2b sidewall
2c Tread
3 lower container
4-upper container
5 intermediate container
5a conical surface
6 outer ring
6a conical surface
7 air bag
10 sidewall forming section
11 lower sidewall forming section
11a lower sidewall design surface
12. Upper sidewall forming part
12a upper sidewall design surface
20. Tread forming part
20a tread design surface
21. Segmentation
22. Retaining member
22a hole
23. Design surface dividing die part
23a backboard portion
23b side plate portion
24 design surface dividing die part
24a back plate part
24b side plate portion
25. Protrusions
26. Rotatable shaft
27. Pin component
28. Seam(s)
29 spring member
30 bolt
30a head
O central axis
Claims (6)
1. A mold for forming a tire for vulcanization molding an unvulcanized green tire into a tire, the mold comprising:
an annular tread molding portion divided into a plurality of segments arranged in a circumferential direction and configured to be opened and closed by moving each of the segments in a radial direction, wherein,
each of the segments comprises:
a plurality of design face dividing mold portions each including a tread design face for forming a tread of the tire, the plurality of design face dividing mold portions being arranged in a circumferential direction of the segment, and configured to rotate about a rotatable shaft parallel to an axis of the tread forming portion when the tread forming portion is opened after vulcanization forming of the tire.
2. The mold for forming a tire as in claim 1, wherein,
each of the segments comprises:
a retainer driven radially outward by the container when the tread forming portion is opened, and
each of the plurality of design face-dividing mold portions is rotatably supported by the rotatable shaft with respect to the holder.
3. The mold for forming a tire of claim 2, the mold comprising:
the two pieces of said design face divide the mould part, wherein,
a rotatable shaft corresponding to one of the design face dividing mold portions is arranged on one circumferential end side of the holder, and a rotatable shaft corresponding to the other of the design face dividing mold portions is arranged on the other circumferential end side of the holder.
4. A mold for forming a tire as in claim 3, wherein,
the design surface dividing mold portion includes a back plate portion and a pair of side plate portions extending radially inward from both ends of the back plate portion in the axial direction and supported by the rotatable shaft at the back plate portion.
5. The mold for forming a tire as in any one of claims 2 to 4, wherein,
a spring member is attached between the design face dividing mold portion corresponding to the spring member and the holder to hold the design face dividing mold portion corresponding to the spring member at a predetermined position, and when the tread forming portion is opened, the spring member is elastically deformed to allow the design face dividing mold portion to rotate relative to the holder.
6. A tire production method for producing a tire by vulcanization molding an unvulcanized green tire using a mold for forming a tire, the mold comprising an annular tread molding portion which is divided into a plurality of segments arranged in a circumferential direction and is configured to be opened and closed by moving each of the segments in a radial direction, wherein,
when the tread forming portion is opened by moving each of the segments radially outward, the tire is demolded from the tread forming portion with each of a plurality of design face dividing mold portions provided in the segments in a circumferentially aligned manner rotated about a rotatable shaft parallel to an axis of the tread forming portion.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021103645A JP2023002401A (en) | 2021-06-22 | 2021-06-22 | Tire molding die and tire production method |
| JP2021-103645 | 2021-06-22 | ||
| PCT/JP2021/043044 WO2022269939A1 (en) | 2021-06-22 | 2021-11-24 | Tire molding die and tire production method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117529396A true CN117529396A (en) | 2024-02-06 |
Family
ID=84544373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180099314.XA Pending CN117529396A (en) | 2021-06-22 | 2021-11-24 | Mold for forming tire and tire production method |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP4360843A1 (en) |
| JP (1) | JP2023002401A (en) |
| CN (1) | CN117529396A (en) |
| WO (1) | WO2022269939A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117564224B (en) * | 2024-01-17 | 2024-04-23 | 山东豪迈机械科技股份有限公司 | Gypsum ring for casting tire mold |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2597783B1 (en) * | 1986-04-25 | 1988-08-26 | Michelin & Cie | RIGID MOLD FOR MOLDING AND VULCANIZING TIRES |
| JP3810585B2 (en) | 1999-05-18 | 2006-08-16 | 三菱重工業株式会社 | Tire vulcanizer |
| JP4138153B2 (en) | 1999-05-31 | 2008-08-20 | 三菱重工業株式会社 | Tire mold segment drive device |
| ES2274056T3 (en) * | 2001-07-17 | 2007-05-16 | Bridgestone Corporation | VULCANIZATION MOLD FOR A PNEUMATIC COVER. |
| JP4346084B2 (en) * | 2004-07-06 | 2009-10-14 | 東洋ゴム工業株式会社 | Mold for tire molding |
| US7572120B2 (en) | 2007-12-20 | 2009-08-11 | The Goodyear Tire & Rubber Company | Tire mold |
-
2021
- 2021-06-22 JP JP2021103645A patent/JP2023002401A/en active Pending
- 2021-11-24 EP EP21947218.0A patent/EP4360843A1/en active Pending
- 2021-11-24 CN CN202180099314.XA patent/CN117529396A/en active Pending
- 2021-11-24 WO PCT/JP2021/043044 patent/WO2022269939A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| EP4360843A1 (en) | 2024-05-01 |
| JP2023002401A (en) | 2023-01-10 |
| WO2022269939A1 (en) | 2022-12-29 |
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